When constructing buildings, parking garages, and other structures, grid shoring systems are often used to carry a load while structural concrete sets or permanent beams are fixed in position. The grid shoring systems may include platform supports that support multiple main beams on head assemblies that include seats. The main beams are typically installed by lowering each main beam onto the seats of adjacent head assemblies, and the main beams and seats may support a plurality of secondary beams extending between parallel main beams. One or more panels may rest on the main beams and secondary beams to form a platform that carries the load.
Typically, the platform support is raised or lowered to position the platform at the correct height for the structure that is being supported. Platform supports often utilize drop head assemblies that may ease the removal of the platform and the platform support. A drop head assembly typically includes a floating seat that is held in position by a seat support plate, which, in turn, is retained by a pin extending through the drop head assembly. When the seat support plate is rotated, both the seat support plate and the seat pass over the pin, dropping the platform and allowing for easy removal of the platform and platform supports.
Recently, platform supports have been developed include both upper and lower head assemblies, allowing the platform supports to position platforms at different heights and support structures at different levels, while reducing the total number of platform supports. Although drop head assemblies have been used for the upper head assembly, using such an assembly for the lower head assembly would typically prevent the platform support from being raised or lowered. This is because the pin that extends through the drop head assembly would prevent the use of a telescoping-type assembly that is commonly used to adjust the height of the platform support. Therefore, the lower seat is usually fixed in position on the head assembly. Although this arrangement does allow for both upper and lower platforms, the upper platform must be removed before the lower platform, which rests on the fixed heads, can be removed. Further, additional head assemblies must be purchased since the upper and lower head assemblies are not interchangeable.
What is needed, therefore, is a head assembly that can drop a platform independently of other platforms and be used as both an upper head assembly and a lower head assembly, allowing for a reduction in the number platform supports and heads that are used.